Liquid level gauge



Feb-29, 1944. M. RbvER LIQUID LEVEL GAUGE Filed May 21, 1940 INVENTOR.

SQMA Martin R'zrer Patented Feb. 29,

UNITED 2,342,696 romo LEVEL GAUGE Martin Rover,

Jessnitz/Anhalt, Germany; vested in the Alien Property Custodian Application May 21, 1940, Serial No. 336,381 In Germany May 80, 1939 2 Claims.

appgatus far measuring the depth of liquids in tan The measuring apparatuses for liquids hitherto known show one or several of the following defects: Incorrect registration or complete failure, if slight leaks occur in the conduit pipes, furthermore dependence of the registration on the -temperature of the conduit pipe, sensitivity against rough treatment, low emciency, which causes low adjusting power of the indicating or recording apparatus. If electricity is used as an auxiliary power, delicate, fine, mechanical parts have to be employed and special protective measures have to be taken when working with explosive substances. Mercury, furthermore, is used as contact liquid for many electrically operated remote indicating apparatuses which, however, in many cases isobjectionable from a purely chemical view point.

It is an object of this invention to construct an indicating apparatus for measuring the depth oi liquids in tanks etc.

Another object is the construction of an apparatus which is adaptable without danger to highly inflammable liquids.

These and other objects will be app r nt from the following description.

A remote indicating apparatus for measuring liquids not showing any of the above mentioned disadvantages will be described hereinafter. It is designed to measure the depth of liquids in tanks, which are intended for work or storage,

the depth of which liquid is diiiicult to determine by other measuring apparatuses, especially when the tanks are submerged or kept under high pressure. By the present invention it is also possible to construct an apparatus which is adaptable without danger to'inflammable liquids, because it avoids electric current and the like. The apparatus works according to the compensation principle by using compressed air, which doesnot come into contact with the liquid with which it may form an explosive gas-mixture.

The apparatus uses the known principle of measuring the buoyancy of a body submerged in the liquid, this buoyant body may be partly submerged for instance when measuring the depth of liquids, or completely submerged when measuring their density. The buoyant .body may paratus. Accordingto the present invention this buoyancy is measured by; means of that pres-.

be adiusted to the-form of the tank, in order to obtain an even graduation of the-indicating ap- This invention relates to a remote indicatin lating itself, which is necessaryto hold the buoyant body always at the same height. As the measuring apparatus performs small movements only around the zero-position, it is possible to transmit these movements outside the tank through an elastic membrane-packing free from friction. This membrane can be made, contrary to membranes for a deflection method, of flabby, non-stiff material.

To use such a membrane makes it possible to rigidly connect those parts of the transmitting system which are arranged outside the tank with those parts which are arranged inside the tank.

In the accompanying drawing which illustrates this invention Fig. 1 is an elevation, partly in section, of the liquid level gage embodied in this invention; Fig. 2 is an elevation, partly in'section, showing a modified form of float; Fig. 3 is a side sectional view of Fig. 1 taken on the line 3-3; and Fig. 4 is a plan sectional view of Fig. 2 taken on the line l-J.

In the drawing l designates the tank for the liquids and I the buoyant body. This buoyant body is mounted in the tank in. such a way, that it begins shortly above the bottom of the tank and reaches up to the highest possible point of the liquid. This buoyant body 2 hangs-on one arm of a double-armed lever 3 the other arm of which extends outside the tank through the gas tight bellows membrane 6. A fork l5, rigidly connected to the lever 3, grips around the membrane 6 and has, on each side a spindle bearing II which is rotatively mounted in a bearing il rigidly connected with the tank. The said spindle bearings i support rotative axle it which penetrates through the middle of the membrane 8 supporting lever I through bearing 4. The force of the tank-pressure efl'ective on the membrane in a horizontal direction is also taken up by this arrangement.

The lever 3 carries on its right end a movable counter balance 5, to compensate the weight o; the buoyant body when the tank is empty If the buoyant body 3 is raised in thetan the other hand by means of jthe adioined piece iii reieasesthe'opening of the nozzle 0 for com- I ressed air. By this nozzle I so much compressed "air enters into the chamber ii, that membrane 3 and with it the lever 1 and the double-armed lever 3 are brought back into the original position, by lowering of the buoyant body I. The pressure oi the compressed air behind the membrane, which is admitted into the chamber it to oom= pensate for the raising of the buoyant body 2, is therefore a measurement for the depth of the lio uid in the tank l. The air (or gas) pressure we isting there is measured by any suitable appare tus, for instance: as illustrated in the drawing with an ordinary manometer 13. If the contents of the tank decrease, the pressure 01 the com== pressed air in the chamber I i must be adjustable. A blow-ofl-nozzle I2 is therefore provided, which preferably is built in an adjustable manner. By adjusting this nozzle, leakages in the pipes may be compensated and are in this way not dangerous any more.

As the membrane always automatically main tains the right pressure within the remote messuring apparatus, changes of temperature are without influence on the resulting measurement. Likewise a change of the length 01. the conduit pipes is always possible. Also further indicating, registering or regulating devices may be used. without further readjustment.

Membrane 8 forms an important part in male ing the Outside parts of the apparatus air tight against the inside parts of the tank, since the apparatus works according to a compensation method, thereby registering small movements 1 around the zero-position. This membrane can be constructed so strongly that the apparatus may be used without dimcultles ror tanks oi con 'siderable pressure (at the present about 25 at mospheres) and still possess high accuracy and excellent adjusting power.

Another important part, moreover, is the buoyant body 2. The weight of this body is somewhat greater than that of the quantity of water oils placed by it but is preferably not so large as to cause unnecessary loading or the double lever 3,

The body may consist of massive material. in most cially sensitive for a co re nesaooo This finds a most useful application for reaction vessels in chemical factories. Also the overflowing of storage tanks may be indicated in a striklog manner and in time, by an increased scale movement being caused by a special form of the buoyant body.

Figure 2 shows diagrammatically a cross sectlonal View of a buoyant body. simple form of the buoyant body employed in a reaction vessel, wherein exact measurement of the chemicals to be added is made possible by the enlargement 2c.

The new apparatus is of wide use, It may be employed for instance to measure specific weights of liquids, if the buoyant body is completely submerged. Furthermore it may serve as a regula- I tor for regulating the depth, the contents or the density or the liquids. In connection with a regu letting deviceicontrolled by compressed air, it may be used directly as a. regulating device of the store-said hind.

What Ill c lm is:

Satin; for indicating the level of a horrid in a easel under pressure, which comprises a float suspended within said vessel, said float having a height extending from a point just above the bottom or the vessel to the highest possible level oft said liquid, e pressure-tight bellows membrane, a double armed lever pivotally supported Within said bellows membrane, one arm of said lever supporting the float and the other arm being, provided with a counterbalance, a pressure chamber, a diaphragm. within said pressure chamber and. defining one Wall thereof. mean; connected to said. one arm of the double armeo lever and adapted to transmit the movement oi the float to the diaphragm, mears controlled by the movement of said diaphragm for placing said pressure chamber under a pressure equal and opposite to that created by the movement of said vzllaphragm, and means for indicating the pressure within. the pressure chamber.

2?, An apparatus as defined in claim 1, wherein the means for transmitting the movement of the heat to the diaphr ,m is connected to the advise. 

